The majority of McCarron’s passes in the NFL so far came over his three starts at the end of the 2015 season. Over that stretch, the Bengals beat the 49ers and Ravens, each of whom finished 5-11, and lost in overtime to the eventual Super Bowl-champion Broncos.

McCarron completed 54 of his 83 passes (65.1 percent) over that stretch with four touchdowns and no interceptions. That may look impressive and was good enough for a 100.1 passer rating as a starter, but the problem was that the Bengals’ offense slowed to a crawl.

There’s probably still at least one more piece to be added to make life easier for Keenum.

Broncos offensive coordinator Bill Musgrave was able to piece together a division-winning offense in Minnesota with Christian Ponder, but that was with an MVP-caliber season from Adrian Peterson.

(Musgrave then went to the Raiders, where the offense fell apart immediately after he left, so there’s that.) If the Broncos can keep Keenum in situations in which he is facing third-and-manageable and can pick apart zone coverages, he’s going to do just fine.

There’s no worse nightmare for a Super Bowl contender than losing the starting quarterback toward the tail end of the season. That’s why Foles was arguably the biggest addition in retrospect. Foles is a good reminder that even those backup signings that are easy to dismiss could be hugely important down the road.

Foles completed 72.6 percent of his passes in the postseason, averaging over 323 yards per game. He threw three touchdown passes against the top-ranked Vikings’ defense in the NFC Championship, and threw for three more and added a receiving score against the Patriots in his Super Bowl 52 MVP performance.

Smith also chipped in with a few drops, which didn’t help matters.

The Panthers needed wideout help alongside Devin Funchess, but it’s hard to figure that they were really bidding against other teams who wanted to assume Smith’s contact for 2018 and trade an asset in the process.